Unlabeled.E
type vertex
= V.t
type t
= V.t * V.t
val compare : t -> t -> int
val src : ('a * 'b) -> 'a
val dst : ('a * 'b) -> 'b
type label
= unit
val label : 'a -> unit
val create : 'a -> unit -> 'b -> 'a * 'b